From 01caff945377ecd54ebf4badae97c700fae6a3ac Mon Sep 17 00:00:00 2001
From: Willi Braun <wbraun@fh-bielefeld.de>
Date: Thu, 18 Feb 2016 12:59:09 +0100
Subject: [PATCH] added differentiation rule for built-in sum call

---
 Compiler/BackEnd/Differentiate.mo | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Compiler/BackEnd/Differentiate.mo b/Compiler/BackEnd/Differentiate.mo
index ae59c2d4410..851f8b18d71 100644
--- a/Compiler/BackEnd/Differentiate.mo
+++ b/Compiler/BackEnd/Differentiate.mo
@@ -1590,6 +1590,14 @@ algorithm
         (exp_1, _) = Expression.makeZeroExpression(Expression.arrayDimension(tp));
       then (exp_1, inFuncs);
 
+    case ("sum",_)
+      equation
+        tp = Expression.typeof(exp);
+        (exp_1, funcs) = differentiateExp(exp, inDiffwrtCref, inInputData,inDiffType,inFuncs, maxIter, expStack);
+        exp_2 = Expression.makePureBuiltinCall("sum",{exp_1},tp);
+      then
+       (exp_2, funcs);
+
     case ("max",DAE.ARRAY(array=expl,ty=tp))
       equation
         tp = Types.arrayElementType(tp);